Tamoxifen, 500 mg

A small molecule from STEMCELL Technologies, tamoxifen is a selective estrogen receptor modulator with tissue-specific antagonistic or agonistic effects. It acts on the two homologous nuclear receptors for the hormone estrogen (estradiol), known as ERα and ERβ, which upon activation form homo- and hetero-dimers that interact with accessory proteins to regulate gene transcription. The compound is widely used to conditionally activate Cre-ER in transgenic models, enabling inducible Cre-mediated recombination.

Published research applications include cell line development using tamoxifen-inducible Cre-ER systems, as well as cancer research, where it inhibits growth in the human breast cancer cell line MCF-7 and acts as an antagonist of estrogen receptor action in breast tissue and breast cancer cells. The product has a molecular weight of 371.5 g/mol and a chemical formula of C₂₆H₂₉NO, with a purity of ≥ 95% (CAS Number 10540-29-1).

Tamoxifen is supplied as a crystalline solid with low solubility in aqueous media. It is soluble in DMSO and absolute ethanol. The product is stable at -20°C as supplied and should be protected from prolonged exposure to light. Stock solutions should be prepared fresh before use, and aliquoting is recommended to avoid repeated freeze-thaw cycles. This product is hazardous; users should consult the Safety Data Sheet. A California Proposition 65 warning applies, as tamoxifen and its salts are known to the State of California to cause cancer.